A full write-up on the RCA pavilion starts at:
http://www.nywf64.com/rca01.shtml
especially the "see yourself" part at
http://www.nywf64.com/rca04.shtml.
They used a series of rollers, rather than bins, between the machines. I was absolutely floored when I saw it. I have been pissed with myself ever since that I didn't take a picture of the arrangement.
The technical difficulty was of course completely lost on the average visitor, but I was well aware of the "tape banding" that would show up frequently in on-air programs at the time. I think this was a tremendous bragging piece within the industry, to have three machines that were completely compatible with no "tape banding" visible. The servos and automatic correction circuitry had only recently reached this level of performance.
Some people I know in the TV industry have told me of doing both roller and binned delays. One binned setup, I was told, could do a 30-minute delay!